1. Technical Field
The present invention relates to a screen and a projection system, and particularly to a technology of a screen used with a projector that projects light representing an image signal.
2. Related Art
A projector projects light representing an image signal and uses the light reflected off a screen or the like to display an observable image on the same side as the projector with respect to the screen. On the other hand, when the light representing an image signal passes through a screen or the like, an observable image can be displayed on the side opposite to the projector with respect to the screen. When a screen that can reflect and transmit light is used, a projector disposed on the viewer's side with respect to the screen and a projector disposed on the side opposite to the viewer with respect to the screen can be used for effective display. For example, JP-A-9-114003 and JP-A-2006-227581 propose technologies of screen that reflects and transmits light. JP-A-9-114003 proposes a configuration using a translucent film that reflects and transmits light. JP-A-2006-227581 proposes a configuration in which light having a specific polarization component is reflected whereas light having another polarization component is transmitted.
In the technology described in JP-A-9-114003, substantially half the projected light that is intended to be reflected off the screen passes through the translucent film, and substantially half the projected light that is intended to be transmitted through the screen is reflected off the translucent film. Therefore, approximately half the light that the projectors have projected is lost, so that sufficiently bright display is difficult to achieve. Further, since the light reflected off the diffuser layer and the light transmitted through the diffuser layer mostly diverge in the direction away from the projectors, likely resulting in a non-uniform light intensity distribution on the screen in which areas closer to the periphery of the screen are darker. In the technology described in JP-A-2006-227581, since the light from one projector is divided into two directions, sufficiently bright display is difficult to achieve, likely resulting in a non-uniform light intensity distribution as in JP-A-9-114003. Further, since the display on one side of the screen is reversed right and left from the display on the other side of the screen, the technology is not suitable for applications involving display of characters and the like, and hence only suitable for limited applications. As described above, both the technologies of related art encounter difficulty obtaining a bright image with a uniform light intensity distribution by reflecting and transmitting light.